Bad Day at the Track...

[zraffz]

I used to race a T5 TA at the track but it was my first time with a T56 in a LT1. On the way down my 95 Formula (t56) was having a slight vibration in the clutch pedal if I didn't apply any pressure to it. I figured since it was the first time I had drove the car in sneakers that it had always did that (I drive to work and town in boots).

Well my first pass down the track I launch at 2,100 RPM and ease into the gas. The tires spun like hell and I kept backing off the gas more and more, I assume because I did that the skip shift kicked in and wouldn't let me put the car into 2nd or 3rd so I threw it into 4th and then quickly pulled it back out and tried going into 2nd without any luck. Rolled for about 2-3 seconds and kept re-clutching trying to get into 2nd without any luck. Finally I threw it into 3rd and it slid right into gear. At that point I knew my time was screwed so after I pulled 3rd to about 5,600 I just popped it into neutral and rolled 100+ feet through the traps.

I stopped to get my time slip and my car started to shake, almost like it was missing very badly. My clutch peddle felt fine at this point and I eased it into gear and started to roll while it felt like somebody was picking up my car and shaking it. At about 2 grand the shake went away so I limped it to a parking spot. Thinking I just blew a head or intake gasket I checked my oil. From there I looked and saw I had two wires sitting on the header. In neutral I slowly revved the car up to about 4,500 RPM and it felt like the bottom end was out of balance... the higher in the RPM I went the worse it got. Their was a slight knocking noise but it was very hard to hear over my exhaust and wasn't echoing through my tail pipes like I normally diagnose with a rod knock.

In that pass down the track I didn't over rev the car at all but the symptoms make me feel like I did. The ride home wasn't much fun either and it was impossible to leave lights without smoking my clutch. By the time I got home (45 minutes later) I had half a clutch peddle left.

End result is a horrible vibration, knocking/chattering sound and a smoked clutch.

I will be hitting it with the compression gauge; it feels like their is a lack of a compression and the feeling/sound says so as well. At this point I know I'm defiantly in it for a clutch and if I'm separating my block and trans I'm pulling the car off the road and building what I want.

Oh and it went 15.6 @ 87 MPH (remind you I spun first to a 2.6 60'), went from 1st to 3rd and let off about 100' before the trap.

[JL8Jeff]

Are you saying 2 spark plug wires were on the header? If so, you probably melted them and you're getting misfires. Check that first. As for the clutch, check the fluid in the reservoir and maybe try bleeding it.

[Blackbirdws6]

Burnt wires will cause misfires and generally make the engine run pretty crappy. Get those fixed and check the others before you get more involved in the diagnosis.

How many miles do you have on the trans? Shifting issues like that could be a few things like synchros, hydraulics, etc. Check the clutch fluid for debris or general cleanliness as a start.

[zraffz]

It does have two burnt wires but it doesn't feel like a miss, it's not jolting forward to back like a vehicle normally does when it breaks up but it feels as if it's shaking left to right as if some sort of rotating mass is out of balance.

[Blackbirdws6]

Originally Posted by zraffz

It does have two burnt wires but it doesn't feel like a miss, it's not jolting forward to back like a vehicle normally does when it breaks up but it feels as if it's shaking left to right as if some sort of rotating mass is out of balance.

If a cylinder is not firing, it will throw the engine out of balance and could def cause it to shake. You can dig in further but I would just replace the wires and go from there.

[zraffz]

Originally Posted by Blackbirdws6

If a cylinder is not firing, it will throw the engine out of balance and could def cause it to shake. You can dig in further but I would just replace the wires and go from there.

I've never had two cylinders completely lack spark so I'm not sure of the feeling. It's a steady powerband throughout the RPM, defiantly lagging but it's not surging or breaking up. I'll be changing them just to double check though.

[sweetbmxrider]

Start cheap, no point in rebuilding an engine over burnt ignition wires.

[zraffz]

Now that I'm not at the track surrounded by loud cars I have time to listen and analyze.
I want to rebuild the motor still but it defiantly sounds like it's missing badly.

Since the car needs it anyway I will be checking the injectors, replacing the fuel filter, wires, and cap/rotor.

[sweetbmxrider]

Heh, cap/rotor, you might want to google "opti replacement" first.

[Adam1978]

i've had spark plug wires melted by headers, sounds a lot like your vibration/missing problem. i always ziptie mine up to other misc hoses now

[zraffz]

Originally Posted by sweetbmxrider

Heh, cap/rotor, you might want to google "opti replacement" first.

I've replaced one already on another car. Not at all difficult, took about 4 hours.

[baddest434]

Originally Posted by zraffz

in a LT1.

theres the problem

[sweetbmxrider]

Originally Posted by zraffz

I've replaced one already on another car. Not at all difficult, took about 4 hours.

Ah ok, wasn't sure if you were familiar. Check to see if there is excessive play in the rotor shaft.